Shark repelling field generating cord

ABSTRACT

A cord having two electrodes for generating a shark-repelling electromagnetic field about a user. The cord is connected to a field generator supported by the user, and in use, maintains contact with surrounding water, even if the user is out of the water.

TECHNICAL FIELD

This invention relates to devices and applications for generatingelectric fields about a swimmer.

BACKGROUND TO THE INVENTION

Numerous devices are known for the purpose of repelling aquaticcreatures. The majority of these devices are designed to generate anelectromagnetic field in close proximity of a diver or to form a barrieror boundary in the nearby water.

Most studies are conducted on the aquatic creature sub-group ofelasmobranchii, otherwise known as sharks. Most shark repellingapparatus use electromagnetic pulses, delivered into the water bysubmerged antenna or electrodes, to create an appropriateelectromagnetic field in the vicinity of the diver.

Various types of pulse generators are used, the characteristics of whichinclude a specification of its duration, repetition rate, amplitude anda pulse rise time. The value or ranges of each characteristic arecarefully selected so as to create the electromagnetic field deemed mosteffective.

In the past, such field generators have been disposed on the body of theswimmer. For example, a field generator unit might be attached to scubaequipment of a diver which would produce a shark repelling zone aboutthe diver. While generally effective, this arrangement suffers from anumber of disadvantages particularly, if the swimmer is not otherwiseencumbered by other apparatus or if the swimmer is for example engagingin surfing and is not continually in the water. This will result in theprotective field being absent for a proportion of time, and thusreducing its effectiveness.

It is an object of the present invention to provide a device which maybe used effectively by swimmers and those who spend a proportion oftheir time outside of the water, such as surfers, when standing on asurfboard.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda cord supporting two electrodes for generating an electromagnetic fieldabout a user to repel selected aquatic creatures, when in use, the cordand electrodes are connected to an electromagnetic field generator andthe supported electrodes are able to make contact with surrounding watereven if the user is not in contact with the water.

Preferably, the distance between the two electrodes may be varied. Theelectrodes may be retrofitted to the cord, or may be incorporated withinthe cord.

A first end of the cord may be connected to the electromagnetic fieldgenerator which may be housed in an ankle cuff worn by the user.

The second end of the cord may be left free, or may alternatively, beadapted to be attached to a surfboard.

Preferably, the cord is made from elastomeric material.

The cord is preferably, in use, connected to the electromagnetic fieldgenerator in the ankle cuff via a resilient flexible protrusionextending from the ankle cuff.

According to a second aspect of the present invention, there is provideda method of providing a shark-free region about a user, the methodincluding supporting two electrodes an a cord connected at one end, to ashark-repelling electromagnetic field generator supported by the user,such that the supported electrodes are able to make contact withsurrounding water even if the user is not in contact with the water.

Preferably, the shark-repelling electromagnetic field generator issupported by the user in an ankle cuff worn about the user's ankle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to thefollowing figures in which:

FIG. 1 shows the legs of a swimmer wearing the device of the presentinvention;

FIG. 2 shows a surfer wearing the device of the present inventionstanding upright on a surfboard;

FIG. 3 shows a surfer wearing the device of the present invention; and

FIG. 4 shows the surfer wearing the device of the present invention andlying on a surfboard.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the legs of a swimmer 10 wearing a cuff 20 about one leg towhich is attached cord 30. The end of the cord 30 distal to the swimmer10 may be left free, or if the swimmer 10 is surfing, the end may beattached to a surfboard (not shown in FIG. 1). If left free, cord 30will simply trail behind swimmer 10, and generate a shark-free zoneabout the swimmer.

Supported by cuff 20 is a standard electromagnetic field generator 40which is also electrically connected to cord 30. Of course, it will beunderstood that field generator 40 may be supported at any otherconvenient place on the user, such as the hip or the upper thigh. Asuitable field generator may be such as described in Australian PatentNumber 669806, to Natal Sharks Board.

Supported by cord 30, are two electrodes 50 a and 50 b which uponstimulation by electromagnetic field generator 40, emit anelectromagnetic field therebetween (not shown).

Cuff 20 is made from a flexible non-conductive and non-slip syntheticmaterial which may be wrapped around and attached to the leg of theswimmer 10 in any known conventional manner, including straps withVelcro or buckles. Extending from the surface of cuff 20, is a resilientflexible protrusion 21 as shown in more detail in FIG. 2. Flexibleprotrusion 21 acts as a shock absorbing device and allows theelastomeric cord 30 to clear the particular part of the body or limb towhich it is attached.

Electrodes 50 a and 50 b are made from a conductive material and may befabricated in the form of flexible coil springs or as a woven braid. Theelectrodes may form co-axial slip-on covers that may be fitted over theelastomer cord 30 and could, if desired, slide freely along its lengthuntil required to be fixed in spaced relationship with each other. Theelectrodes will be of a nominated length and may be set a prescribeddistance apart, depending upon the desired strength of theelectromagnetic field. Typically however, the distance between thecentres of the two electrodes 50 a and 50 b would be in the order of 800mm to 900 mm.

It will be understood by the person skilled in the art that theelectrodes need not be formed to be strictly co-axial with cord 30. Forexample, electrodes 50 a and 50 b may be attached to cord 30 by othermeans and allowed to run parallel to and slightly distanced from cord30. Alternatively, electrodes 50 a and 50 b may be built within cord 30co-axial with or otherwise upon manufacture of the cord if desired.

Each electrode 50 a, 50 b is electrically connected to generator 40 by arespective conductive wire, either externally or internally of the cord30. This may be accomplished by any suitable means as would be known tothe person skilled in the art.

In use, the elastomeric cord 30 is worn by swimmer 10 by attachment tocuff 20 at one end of cord 30 and attached to the surfboard 60 (FIG. 2)at the other end of the cord 30, as is conventional practice. In thisway, surfers may retain their board in circumstances where they areforced off the board and into the water. Cord 30 then allows the swimmer10 to easily regain their board and resume surfing.

According to the present invention, the cord 30 acts in the conventionalmanner but is also used as a propagating antenna for the shark repellingsignal generator 40.

An alternative embodiment is shown in FIG. 3, in which a conventionalsurfing leash 31 is attached to cord 30 as a separate unit.

The present invention provides a further advantage in that it enhancesthe electromagnetic field generated by always allowing “best effect”electrode contact with the water as cord 30 naturally hangs down belowthe water line and creates a protective zone underneath the board andextending out and around the swimmer 10 as shown in FIG. 4.

Whether lying on the board 60 or sitting on the board 60, cord 30remains in the water 70 generating electromagnetic field 80 whichfollows the surfer the entire time the surfer is in or out of the water70.

When a swimmer 10 stands on top of the wet surfboard 60, the body isexcluded from the electrical path created by the electrodes and thewearer feels no annoying skin stimulus. This lack of stimulus alsoapplies when a surfer is lying or sitting on the board. Flexibleprotrusion 21 also aids to guide cord 30 away from swimmer 10 andparticularly from the space between the swimmer's feet and the surfboard60.

The above has been described with reference to a particular embodimentand it will be understood by the person skilled in the art that variousmodifications and additions may be made within the scope of the presentinvention.

1. A cord supporting two electrodes for generating an electromagneticfield about a user to repel selected aquatic creatures, when in use, thecord and electrodes are connected to an electromagnetic field generatorand the supported electrodes are able to make contact with surroundingwater even if the user is not in contact with the water.
 2. A cordaccording to claim 1, wherein the distance between the electrodes may bevaried.
 3. A cord according to claim 1, wherein, in use, a first end ofthe cord is connected to the electromagnetic filed generator which ishoused in an ankle cuff worn by the user.
 4. A cord according to claim1, wherein a second end of the cord is left free.
 5. A cord according toclaim 1, wherein a second end of the cord is adapted to be attached to asurfboard.
 6. A cord according to claim 1, wherein the electrodes areretrofitted to the cord.
 7. A cord according to claim 1, wherein theelectrodes are incorporated within the cord.
 8. A cord according toclaim 1, wherein the cord is made of an elastomeric material.
 9. A cordaccording to claim 3, wherein, in use, the cord is connected to theelectromagnetic field generator in the ankle cuff via a resilientflexible protrusion extending from the ankle cuff.
 10. A cord accordingto claim 1, wherein the selected aquatic creature is a shark.
 11. Amethod of providing a shark-free region about a user, the methodincluding supporting two electrodes on a cord connected at one end, to ashark-repelling electromagnetic field generator supported by the user,such that the supported electrodes are able to make contact withsurrounding water even if the user is not in contact with the water. 12.A method according to claim 11, wherein the shark-repellingelectromagnetic field generator is supported by the user in an anklecuff worn about the user's ankle.